1894,] OF THE STEGANOPODES. 161 



Ornithotomists are agreed that the Steganopodes, considered as 

 a whole, constitute a well-defined group, but beyond this the 

 majority are reticent as to the question of the affinities existing 

 among the families and genera composing it, and its relations 

 as a whole to other avian groups in the system. 



If from among the Pelecanidce we select the genus Phalacrocorax, 

 there is no doubt, so far as its osteology indicates, that it is 

 closely related to the genus Anhinga. This, as has been shown in 

 my work, is evident from a direct comparison of the corresponding 

 bones of the skeleton of any species of Cormorant with tliose of 

 the skeleton of Anhinga. 



On the other hand, and by similar methods, there is no dis- 

 guising the kinship existing between Phalacrocorax and Sulci, 

 although the gap bet\^een these genera is somewhat greater than 

 that between the Cormorants and the Anhiugas. 



Pelicans of the genus Pelecanus are aberrant forms which, as 

 osteologically indicated, have varying relations with all three of 

 the genera thus far mentioned. They are, however, apparently 

 more nearly related to the Sulidce than to the Cormorants. 



From the Pelecanoidea the passage to the Phaethontoidea is not 

 far to seek, for, upon comparing the corresponding bones in the 

 skeleton of such a Gannet as Sula breusteri with those of Phaiithon 

 Jlavirostris, we are at once confronted with so many points of 

 similarity as to leave no doubt upon our minds that it is between 

 the genera and families represented by such species as these that 

 the linking of the two groups takes place. 



This is important, for in another direction we are led on the 

 one hand through Phaetlion to the suborder Longipennes, and on 

 the other to the suborder Tubinares — Phaethon Jlavirostris having 

 some osteological characters that strongly suggest Larine affinities, 

 and still more that bring to mind the skeleton of a Pitfflnus. 



With their distinct maxillo-palatines, their perforate nostrils, 

 their hardly coalesced palatines, their four-notched sternum, and 

 with their ilia widely separated from the " sacral crista," taken in 

 connection with numerous other important skeletal characters, 

 the Tropic Birds are fully entitled to rank as a superfamily — 

 the Phaethontoidea. 



There can be no doubt about Fregata, for the skeletal characters 

 seen in its skull, its sternum and shoulder-girdle, its pelvis and 

 limbs, and in its trunk skeleton, as described in detail in my 

 account, stamp it at once, not only as being a form having 

 many skeletal characters completely at variance with those 

 found in average steganopodous birds — such as Cormorants and 

 Gannets — but as a type likewise for which a superfamily must be 

 founded in order to show that these striking departures are fully 

 appreciated by the student of its osteology. As indicated in our 

 scheme above referred to, this superfamily may be designated 

 Fregatoidea. 



The pelvis in Fregata is decidedly more like the pelvis in 

 Phaethon than that bone in other Steganopodes. In its extra- 



Pkoc. Zool. Soc— 1894, No. XL 11 



